First of, it is okay for you to be angry, if you are angry at someone, you should stay away from that person for sometime. Spend some time to understand what actually went wrong. Try to understand the other person's point of view. You can talk to a third party about what happened, this will help you let go of the stress. Engage yourself in activities that will help take away the bad energy. Try visiting the gym or try watching a comedy movie or sitcom.
When you feel a lot better, you should have a talk with this person, explain why you were angry. Give the other person a chance to explain their side of what happened. After this, both of you will find a mutual ground and forgive one another.
The first thing you should do when you are angry at someone is separate your emotions from the action. Take a step back and a deep breath and calm down. Feel the emotion before you take action. Wait until you have perspective on your anger then decide what you should do about it. Try exercising to get some of that negative energy out of you. Doing this will not only clear your head, but it will also help you get out aggression.
Also, you can talk to a neutral third party, such as a trusted family member or a therapist about what happened and why you are angry with this person. Once you have cooled down, then it is safe to sit down with the person and talk to them about why you are angry and tell them how you feel. Be open to listening to the other person's side once you are done explaining your feelings to them because you might only be looking at one point of view.